In the first 3 monthsof a year, Sally spent 72% of her salary. In the next 4 months, she increased her savings by 25%. If Sally earned the same salary of $1800 per month, what is her average monthly expenditure for the 7 months?

Sep 12th 2009, 02:24 AM

tutor.mathitutor

In the first 3 months, expenditure is 72%.
=> in the first 3 months her saving is (100-72)% = 28%.

In next 4 month, she increased her saving by 25%
which is equal to (28 + 28*25/100)% = 35%

There forre in next four months her expenditure is (100-35)% = 65 %.

There for the % average expenditure in 7 months = (72.3+65.4)/7 %
= 476/7 = 68%